Geographical Analysis of Aneurysmal Subarachnoid Hemorrhage in Japan Utilizing Publically-Accessible DPC Database

Since the launch of the novel medical reimbursement system Diagnosis Procedure Combination (DPC) in 2003 in Japan, inpatient data has been accumulated over time as part of a Japanese governmental nationwide database. This is partially accessible by the public, and this study examined the adequacy of this database as epidemiological research material by extracting the data relating to aneurysmal subarachnoid hemorrhage (aSAH) with special attention given to the limitations that this involves. Datasets after 2010 are considered suitable for analysis because of the numbers of participating hospitals and the analysis term. Extracting the data by prefecture, those with a continuously high aSAH incidence were Aomori, Iwate, Akita, Yamagata, Kochi and Kumamoto Prefectures, and those with low aSAH incidence were Kanagawa, Shiga, Kyoto, Shimane and Ehime Prefectures. Although these obtained results are informative, a publically-accessible DPC database has several limitations. Some limitations have been resolved: the analyzed term each year is now 12-months and the number of participating hospitals seems to have stabilized around 1700. However, other limitations such as masking the numbers in each hospital reporting less than 10 patients still exist, so careful and critical interpretation is necessary in utilizing a publically-accessible DPC database. Considering the potential of this database as material for epidemiological research, future analysis of the entire DPC database by qualified researchers is desirable.

日本自2003年推出新型医疗支付制度诊断分组（Diagnosis Procedure Combination，DPC）以来，作为日本政府全国性数据库的一部分，住院患者数据随时间不断累积。该数据库部分内容对公众开放，本研究通过提取与动脉瘤性蛛网膜下腔出血（aneurysmal subarachnoid hemorrhage，aSAH）相关的数据，并重点关注该数据库固有的局限性，以此评估其作为流行病学研究素材的适用性。鉴于参与医院数量与分析周期的考量，2010年之后的数据集被认为适合用于分析。按都道府县维度提取数据后，动脉瘤性蛛网膜下腔出血发病率持续偏高的都道府县为青森、岩手、秋田、山形、高知与熊本县，而发病率较低的则为神奈川、滋贺、京都、岛根及爱媛县。尽管上述研究结果具备参考价值，但可公开获取的DPC数据库仍存在若干局限性。部分局限性已得到改善：每年的分析周期现已统一为12个月，参与医院的数量也稳定在约1700家。然而，其他局限性依然存在，例如对单医院患者数不足10例的数据进行了隐匿处理，因此在使用该公开DPC数据库时，需进行严谨审慎的解读与批判性审视。考虑到该数据库作为流行病学研究素材的潜力，未来应由具备资质的研究人员对完整的DPC数据库展开分析。